In photolithography process steps in a manufacturing process of a semiconductor device, for example, a resist coating treatment for forming a resist film on a semiconductor wafer (hereinafter, referred to as a “wafer”) is performed.
In the resist coating treatment, a resist solution is usually supplied to a center of the wafer with the wafer held on a spin chuck and rotated. The resist solution supplied to the center of the wafer is spread by the centrifugal force to the entire front surface of the wafer to form a resist film on the wafer. Thereafter a so-called edge rinse for removing the resist film on an edge portion of the wafer is performed (see Patent Document 1). The edge rinse can prevent the resist film on the wafer from adhering, for example, to a transfer arm and a chuck of another unit to generate particles.
Incidentally the edge rinse is a treatment for selectively removing only the resist film on the edge portion of the wafer as described above, and if it is performed with the resist film on the wafer not sufficiently dried, the resist film at the central portion of the wafer flows out onto the edge portion of the wafer from which the resist film is to be removed, thereby contaminating the edge portion of the substrate to waste the edge rinse. Therefore, the edge rinse is performed after a resist film is formed on the wafer and the resist film is sufficiently dried.
However, it takes a long time from when the resist film is formed until when the resist film sufficiently dries. Actually, it might take two or more minutes for the resist film to sufficiently dry, depending on the kind of the resist solution, even if the wafer is rotated.
As described above, it takes time to dry the resist film in the prior art, so that the start of the edge rinse is delayed to increase the required total time for the resist coating treatment, resulting in decreased throughput. Accordingly, to increase the efficiency of treating the wafer, for example, it is necessary to install a number of resist coating units in a coating and developing treatment system in which a series photolithography process steps is successively performed, leading to an increased size of the coating and developing treatment system.
[Patent Document]
Japanese Patent Application Laid-open No. H8-107053